Nowadays, the use of televisions is not limited to the reception and viewing of television broadcasts, and they are used for a variety of purposes. For example, by connecting a digital video recorder (DVR) such as a video tape recorder (VTR) and a DVD recorder to a television, it is possible to view contents reproduced by these external devices, and by connecting a home-use game machine, it is possible to enjoy playing games. For this reason, many televisions are equipped with one or more external input terminals, in addition to an antenna terminal for receiving television broadcasts. A user can switch between these input terminals by operating buttons on a remote control or the television body.
Televisions equipped with a number of external input terminals (many of which are high-end televisions) have an advantage of being able to simultaneously connect to a number of external devices such as a DVR and a home-use game machine. On the other hand, there is a drawback in that operations become complicated since it is necessary to manually switch inputs.
Meanwhile, many recent VTRs and DVRs include a tuner, and thus are capable of receiving television broadcasts. When contents reproduction is not carried out in such a VTR and a DVR, it is common that a television broadcast received by the tuner is outputted to the television.
As thus described, it is possible to view a television broadcast even when the input of the television is set to the VTR. However, in the case where the recording of an analog terrestrial television broadcast is carried out, for example, when the input of the television is set to the VTR, it is not possible to view an analog terrestrial television broadcast of another channel. In other words, in order to view a television broadcast of a desired channel, it is easier to use the tuner of the television than using the tuner of the VTR or DVR. In view of this, there exists technology for automatically switching the input of the television by transmitting a command between the television and an external device.
For example, a reproduction device disclosed in Japanese Laid-Open Patent Application No. 2000-350131 sends an instruction signal to a television when the reproduction device starts reproduction. This instruction signal is a signal for switching the input of the television to an output terminal of the television to which the output terminal of the reproduction device is connected. Furthermore, when entering a power-off state, this reproduction device sends, to the television, a signal to instruct that the input of the television should be switched to the antenna or tuner. This makes it possible to display the reproduced video onto the screen of the television, when the reproduction device starts reproduction, and to display the video received by the antenna or tuner of the television onto the screen of the television, when the reproduction device enters a power-off state.
Note that the AV.link standard (CENELECAV.link (EN50157-1, EN50157-2-1, EN50157-2-2, EN50157-2-3)) specifies commands to allow the interoperability between a television, a VTR, and the like. According to this standard, the VTR issues a predetermined command to the television, when the VTR starts reproduction or when the VTR displays a menu screen. This makes it possible to cause the television to transit from the stand-by state to a state in which the television can display a screen of the VTR.